JetBlue TrueBlue - Jet Now, Jet Later: Book today and get $50 off a future flight!

From the web site promo page: Just register for this promotion on jetblue.com then book a roundtrip flight on jetblue.com between January 29, 2009 and February 8, 2009 for travel between February 24, 2009 and March 31, 2009 and we'll send you a $50 voucher good for travel on JetBlue between May 4 and June 17, 2009 (Black out dates of May 21 to May 25 apply). Vouchers will be emailed on or after April 15, 2009. Offer expires 11:59 p.m. MDT February 8, 2009. Restrictions Apply.

Register here: https://www.jetblue.com/deals/tbpromo/enrollment.aspx?promoID=58&hasPromoCode=false&intcmp=hpIMG50voucher20090128

If I book a ticket, under multi city code (LGB to OAK, SJC to LGB) will it still consider as an eligible trip?

If I book 2 tickets...one for me and one for my girlfriend...do we each get $50 vouchers?
If I'm paying for both, do I get a $100 voucher?

The booking window for the $50 credit is pretty short and very close to the dates of eligible travel. I think that this one is more restrictive than previous iterations have been.

You're also going to get the voucher only 2+ weeks in advance of the travel window.

But hey - I guess there's gotta be a couple people out there that this is gonna work for! :)

so can anyone tell me if my trip will be consider as an eligible trip?? or it has to be same city pairing all the way?

If I book 2 tickets...one for me and one for my girlfriend...do we each get $50 vouchers?
If I'm paying for both, do I get a $100 voucher?
No and no.

Booker and traveler must be the same person. If booker and traveler are different, Voucher will not be awarded.
But if you book one as you for you and one as her for her (two separate transactions) then you each will receive a voucher.
If I book a ticket, under multi city code (LGB to OAK, SJC to LGB) will it still consider as an eligible trip?

I do not believe so. I don't see anything anywhere that suggests that open-jaw or two one-way flights qualifies. That's not to say that you won't get lucky, but if you don't get a voucher you won't have much of a leg to stand on when you try to claim it after the fact.

BTW, the full T&C are at the bottom of the page linked in the OP.